In the management of agricultural acreage, particularly fruit orchards, it is conventional practice to combat killing frosts by stationing and operating at spaced intervals throughout the orchard a plurality of orchard heaters. These almost invariably are fed with fuel oil and, for obvious reasons, are known as "smudge pots". The emissions from such heaters create an air pollution problem of wide extent and significant magnitude.
Until recently, it has been thought that the smudge and smoke resulting from the operation of the orchard heaters was a key factor in overcoming the killing frost. However, in recent times this consideration has been discounted. The primary factor in preventing the frost killing of plants is the warming of the ambient air by burning of the fuel.
Concomitantly, with the increasing scarcity and rising prices of fuel oil products, there has arisen the need for the provision of an orchard heater capable of achieving this desired result while at the same time operating efficiently on pelletized wood and other biomass particles, such as whole grain corn, nutshells, comminuted straw and grasses and the like.
It is the general purpose of the present invention to provide such an orchard heater.
It is a further purpose of the invention to provide an orchard heater capable of operation using pelletized wood and other biomass particles which burns hot and clean without the production of smoke and smudge, but with the production of the large volumes of heat requisite to achieve the desired purpose.
It is another object of the present invention to provide an orchard heater of simple, inexpensive construction which is easily stored, transported, and installed; which is adjustable to suit different operating conditions and fuels; and which is reliable and foolproof in operation.
Other objects are the provision of an orchard heater adapted for use with pelletized fuels which may be started easily and rapidly; which produces a large amount of heat during long operating cycles; which during operation is not subject to plugging, either of the feed pellets or of the ash produced; which will not back-burn into the feed fuel during operation; and which will shut off positively at the conclusion of the burning cycle.
Still a further object of the invention is the provision of an orchard heater which is versatile in that it is adaptable for use as a space heater in shops, barns and sheds and which also is adaptable for use as a cooking device, i.e. as an oven or grill.
The foregoing and other objects of my invention are achieved by the provision of an orchard heater which comprises a combustion chamber which sits on the ground and communicates at its top with a chimney or stovepipe and at its side with a firebox.
The firebox in turn is provided with a draft air opening communicating with the exterior and a flue gas opening communicating with the combustion chamber.
A hopper adapted to contain pelletized fuel is mounted on top of the firebox and communicates therewith. It has a fuel discharge opening leading to the firebox.
A combination air-and fuel-flow control is mounted in the firebox across both the draft air opening and the fuel discharge opening. It is adjustable to control the flows of both air and pelletized fuel. Optionally, an oven or grill may be incorporated into the structure of the chimney thereby taking advantage of the emission of hot gas for cooking purposes.